i think the new RX350's require premium since it uses the same engine as the 2IS and Avalon...and I heard that they require the premium gas...as for the RX330's...I heard u can just use regular...i still use regular on my rx400h so whatever...cheaper gas ....although gas prices are getting crazy!

Just about any grade of gasoline would work fine. The manual says higher octane gives better performance, though you may not notice it in everyday driving.

Avoid the 10% ethanol stuff out West, though 89 is cheaper than 87. Ethanol is corrosive (thus 10% max) to fuel system. Ethanol has less energy content compared to gasoline, thus reduce gas mileage. My highway mpg drops from 24-25 in Colorado (no Ethanol in most places) to 20-21 in Kansas with Ethanol. Not worth it.

I would gladly pay $3.00 USD down here to get U.S. quality gas in Mexico. Not happening, so I continue to use the 92 octane Premium, if you can call it that. The few times I have used the lower octane Magna, it blew one of my precats to bits and felt like I had loaded mud into my gas tank. I have friends in other parts of the world paying double what you are paying the U.S.

Just about any grade of gasoline would work fine. The manual says higher octane gives better performance, though you may not notice it in everyday driving.

Avoid the 10% ethanol stuff out West, though 89 is cheaper than 87. Ethanol is corrosive (thus 10% max) to fuel system. Ethanol has less energy content compared to gasoline, thus reduce gas mileage. My highway mpg drops from 24-25 in Colorado (no Ethanol in most places) to 20-21 in Kansas with Ethanol. Not worth it.

Crap. As of April it was required for all gas stations in my state to use 10% ethanol. We have no choice. I thought I noticed a decrease in gas milage but since I only have 1 full tank with this new stuff in thus far I wasn't too sure.

Here in ND the state gov. came up with the big idea to promote E85 by dropping off the state taxes on it. So E85 sells for $.22 less per gallon than the regular stuff. The only condition was that once 1.5 million gallons were sold in the state they would drop the tax break. According to news the other day, that will happen in about 6 weeks. Then it will be the same price as regular. According to the leading consumer magazine, in their testing the E85 runs about 10% less gas mileage than regular. Actual cost for the normal driver over a year was perdicted to be about $150. to $200. more using E85 than regular, even if it was cheaper per gallon. But us Lexus drivers don't have to worry about using it, you can't according to information I found. E85 is very corrosive to seals and gaskets, that is the reason only certain vehicles can use it. So the engine has to be made using seals and gaskets that are inpervious to ethenol. Also found out that those vehicles could really run on 100% ethenol but the 15% gas is added so they can start easier. Seems 100% stuff has a very hard time igniting. So don't use it in your Lexus.

Here in ND the state gov. came up with the big idea to promote E85 by dropping off the state taxes on it. So E85 sells for $.22 less per gallon than the regular stuff. The only condition was that once 1.5 million gallons were sold in the state they would drop the tax break. According to news the other day, that will happen in about 6 weeks. Then it will be the same price as regular. According to the leading consumer magazine, in their testing the E85 runs about 10% less gas mileage than regular. Actual cost for the normal driver over a year was perdicted to be about $150. to $200. more using E85 than regular, even if it was cheaper per gallon. But us Lexus drivers don't have to worry about using it, you can't according to information I found. E85 is very corrosive to seals and gaskets, that is the reason only certain vehicles can use it. So the engine has to be made using seals and gaskets that are inpervious to ethenol. Also found out that those vehicles could really run on 100% ethenol but the 15% gas is added so they can start easier. Seems 100% stuff has a very hard time igniting. So don't use it in your Lexus.

This has me concerned. That 10% Ethanol stuff is in all grades of gas in my state. We have no choice as it is in all brands and all grades. I know little about Ethanol since we never had anything like this before. The cost is the exact same as before so there is no savings cost. In fact, regular just toped over $3.00 a gallon here and Premium is probably going to hit $3.20 very soon. What is the puropose of this 10% Ethanol gas anyway? It seems to cost the same as regular gas, but is less efficient so we get worse gas mileage that probably negates any cleaner burning effect since more gas is being used over the same time frame. Now I have to worry about the long term corrosiveness as well? Damn, this sounds like a bad idea all around.

This has me concerned. That 10% Ethanol stuff is in all grades of gas in my state. We have no choice as it is in all brands and all grades. I know little about Ethanol since we never had anything like this before. The cost is the exact same as before so there is no savings cost. In fact, regular just toped over $3.00 a gallon here and Premium is probably going to hit $3.20 very soon. What is the puropose of this 10% Ethanol gas anyway? It seems to cost the same as regular gas, but is less efficient so we get worse gas mileage that probably negates any cleaner burning effect since more gas is being used over the same time frame. Now I have to worry about the long term corrosiveness as well? Damn, this sounds like a bad idea all around.

Ethanol suffers from a good deal of confusing marketing. First is the ratio of the blend:

Ethanol - 100% alcohol - the straight stuff. Presently used only in Alky Dragsters and IRL cars with engines optimized for the fuel. This product is blended with gasoline to produce two motor fuels.

E-85 - A blend of 85% ethanol and 15% gasoline. The small amount of gasoline in the blend provides quicker starts than pure ethanol - which racers will agree, with it's low vapor pressure is often difficult to light off. This blend requires a "flexible fuel" engine that is rated to handle the corrosive nature of high levels of alcohol in the fuel, and according to the American Coalition for Ethanol, is always clearly marked at the pump and is not intended for non-FFV use.

E-10 - A blend of 10% ethanol and 90% gasoline approved and warranted for use by ALL manufacturers. Ethanol is replacing MTBE (Methyl Tertiary-Butyl Ether) as a gasoline additive because it achieves the same reduction in exhaust emissions without the danger to ground water. California residents have been using it since 2003, when the phase out of MTBE additives, begun in 1999, was complete. In some states, and many large cities, ethanol blends have already replaced MTBE. Ethanol does provide a cleaner-burning fuel blend, even in a 10% solution. It is more expensive than gasoline, but a bit cheaper than MTBE which it is replacing in the blended product.

Ethanol blends provide a number of advantages - including ground water safety, oxygenation of the fuel for reduced air pollution, and cleaner burning in the cylinder. As a renewable resource, it reduces our dependence on fossil fuels. Best of all, it boosts the octane rating of the fuel blend, providing anti-knock properties without having to tinker with the octane-heptane mix to achieve the same effect.

It does, however have a drawback or two: First it is corrosive, requiring an engine and fuel system designed for it. Second, it does not pack the "energy density" of gasoline in BTU's per gallon, meaning that it will not take you as far on a gallon. Finally, it is not presently transportable by pipeline (same corrosive issues as in your engine), and thus trucking costs pretty well overcome any savings over MTBE fuels - particularly in the Midwest.

Crap. As of April it was required for all gas stations in my state to use 10% ethanol. We have no choice. I thought I noticed a decrease in gas milage but since I only have 1 full tank with this new stuff in thus far I wasn't too sure.

Yes, some states require Ethanol usage in winter months. Colorado is coming off it so my gas mileage is coming back up.

It does help clean the exhaust emission, at the expense of fuel economy. At today's high oil price, Ethanol is cheaper compared to gasoline. This is why you see mid-grade selling for less than regular gas in Midwestern states.

At 10% it will be OK for fuel system seals and gaskets. Just don't fuel up with E85 if you see one.

Ethanol suffers from a good deal of confusing marketing. First is the ratio of the blend:

Ethanol - 100% alcohol - the straight stuff. Presently used only in Alky Dragsters and IRL cars with engines optimized for the fuel. This product is blended with gasoline to produce two motor fuels.

E-85 - A blend of 85% ethanol and 15% gasoline. The small amount of gasoline in the blend provides quicker starts than pure ethanol - which racers will agree, with it's low vapor pressure is often difficult to light off. This blend requires a "flexible fuel" engine that is rated to handle the corrosive nature of high levels of alcohol in the fuel, and according to the American Coalition for Ethanol, is always clearly marked at the pump and is not intended for non-FFV use.

E-10 - A blend of 10% ethanol and 90% gasoline approved and warranted for use by ALL manufacturers. Ethanol is replacing MTBE (Methyl Tertiary-Butyl Ether) as a gasoline additive because it achieves the same reduction in exhaust emissions without the danger to ground water. California residents have been using it since 2003, when the phase out of MTBE additives, begun in 1999, was complete. In some states, and many large cities, ethanol blends have already replaced MTBE. Ethanol does provide a cleaner-burning fuel blend, even in a 10% solution. It is more expensive than gasoline, but a bit cheaper than MTBE which it is replacing in the blended product.

Ethanol blends provide a number of advantages - including ground water safety, oxygenation of the fuel for reduced air pollution, and cleaner burning in the cylinder. As a renewable resource, it reduces our dependence on fossil fuels. Best of all, it boosts the octane rating of the fuel blend, providing anti-knock properties without having to tinker with the octane-heptane mix to achieve the same effect.

It does, however have a drawback or two: First it is corrosive, requiring an engine and fuel system designed for it. Second, it does not pack the "energy density" of gasoline in BTU's per gallon, meaning that it will not take you as far on a gallon. Finally, it is not presently transportable by pipeline (same corrosive issues as in your engine), and thus trucking costs pretty well overcome any savings over MTBE fuels - particularly in the Midwest.

Excellent post. Higher "energy density" means a gallon of pure gasoline has about 50% more energy than a gallon of pure ethanol and will take your car 50% farther per gallon. Charging the same for an 85% ethanol blend is a pure rip off. I am glad that the highly toxic MTBE is being replaced in our local gas-insanity to put it in there to begin with. For more than you want to know in an easily digested form click here:Wikilink

They have the mid-grade price the same as regular here every Wednesday. If I can wait, I fill up with the mid.

There are too many factors and cost of premium vs regular is only one factor. Here in Austin each grade is sold at a difference of $0.10 per gallon [The spread has been the same when Gas was $2.50 a gallon or $3.00 a gallon]. The % difference in various grades of gas has infact dropped, with increase in price.

Best way to save money would be to avoid driving all-together. Some say, reduced demand will bring the prices down.